Motor-driven tool mechanism



Jan. 18, 1949; LJUNGGREN 2,459,384

MOTOR DRIVEN TOOL MECHANISM Filed Sept. 11, 1945 nEm-l Patented Jan. 18,1949 UNITED STATES PATENT OFFICE MOTOR-DRIVEN TOOL MECHANISM Thor H.Ljunggren, Charlestown, N. 1-1., assignor to Bryant Chucking GrinderCompany, Springfield, Vt., a corporation of Vermont ApplicationSeptember 11, 1943, Serial No. 501,949

3 Claims. 1

This invention relates to motor driven tools or work holders and whilenot restricted thereto, it has been developed more particularly inconnection with high speed small diameter grinding wheels or similartools driven by high frequency induction or repulsion electric motors.For such high speed spindles, it is important to employ as few bearingsas possible in order to avoid bearing friction. It is also importantthat the motor rotor be accurately concentric with the spindle. It mayalso be desirable to employ grinding wheels or other tools of difierentcontours or cutting qualities or work holders of difierent types fromtime to time in the same machine and to change from one to anotherquickly and in connection with tools with a single chucking or othersupport of the work.

An object of the present invention, therefore, is to reduce to a minimumthe number of bearings required to support the motor rotor and thespindle.

A further object is to facilitate the rapid change from one to anothertool or other device.

A still further object is to provide for permanent alinement of themotor rotor and the spindle.

To these ends the motor rotor and the spindle are made as one and thesame member, and

this member, together with a tool mechanism and the bearings for thespindle, are made as a single unitary structure which may be detachablyassociated with a motor stator and interchangeable with similar unitscarrying mechanism for holding tools of other shape, cutting, or otherqualities, or for supporting work holders, or other devices.

For a more complete understanding of this invention reference may be hadto the accompanying drawings in which Figure 1 is a view partly in sideelevation and partly in section of a grinding wheel spindle and itsmounting, embodying the invention.

Figure 2 is a front elevation of the same.

Figures 3 and 4 are side elevations of wheel and rotor units ofdifferent forms which may be interchanged for the unit shown in Figures1 and 2.

Figure 5 is a view somewhat similar to Figure 1, but showing a modifiedunit and mounting.

Figure 6 is a detail sectional view on line 5-6 of Figure 5.

Figures 7 and 8 are side elevations of units of different forms whichmay be interchangeably substituted for the unit shown in Figure 5.

Referring first to Figure 1, at l is indicated a portion of a machinebed to which is clamped, as by a clamping bar 2, and screws 3, the baseportion 4 of a motor casing 5 within which is secured the stator 6comprising a core and frame of a motor, preferably of the induction orrepulsion type, and preferably also one capable of being excited withhigh frequency alternating current. The rotor f for this motor isfixedly secured to a spindle 8 mounted for rotation within a bearingcasing 9 through which it extends and on the opposite side of which ithas means of any suitable description for securing a tool thereto. Asshown this tool is a grinding wheel :0. The bearing casing 9 may haveany suitable bearing arrangement therein and may, for example, comprisea pair of spaced radial and axial thrust ballbearings, though any otherdesired type of bearing suitable for the particular type of tool may beemployed. This bearing casing, as shown, has at its inner end anoutwardly extending marginal flange l5 and an axially extending flangeH. These flanges i5 and H are arranged to engage the end wall portion 12and the inner face portion [3, respectively, of the motor casing 5, andscrews 14 may be employed to secure the bearing casing 9 to the motorcasing 5, as shown, with the rotor 'l in operative relation to thestator 6.

In Figures 3 and 4 are illustrated other tool units, each comprising abearing casing 9a and 91) within which is journaled a spindle 8 on theinner end of which is mounted the rotor l, and on the outer end of whicha different tool is carried. In each instance a grinding wheel is shownas the tool, the grinding wheels Illa and lob of Figures 3 and 4,respectively, being of different size or cutting quality, or differingin other respects from the wheel I0 shown in Figures 1 and 2. Each ofthese units in its bearing casing 9a or 9b is provided with flanges l5and H identical in size and arrangement with the similarly numberedflanges of the unit shown in Figure 1, so that any of these units may beinterchangeably associated with the stator 6 of the motor casing andwith the machine support which carries this casing. It will thus be seenthat the rotors in all cases are relatively permanently associated withtheir spindles so that their coaxial relation therewith may be assuredand that the entire bearings for the spindle and the motor rotor arecontained within the bearing casing 9, 9a or 9b, so that the number ofbearings may be reduced to a minimum, which is desirable for high speedoperation. Likewise, the tools or work holders which may be supported bythe several spindles of the various units may be of different shapes,cutting qualities, or otherwise difier, but all can be employed with thesame motor stator.

In Figures 5 to 8, a modification is shown in which the stator supportN30 is provided with suitable flanges IOI to which the casing I02 of themotor stator may be secured as by screws I03, the particular statorshown having the windings I04 and being closed over at its outer end bythe cover I05. The support lllil also has a split bearing portion at IIII, the parts of which may be clamped together as by the screws HI andinto clamping relation to a bearing casing H2 of cylindrical exterior.This bearing casing may have journaled therethrough the tool spindle H5carrying the motor rotor H6 at its inner end and a tool, such as agrinding wheel ill, at its outer end.

Other units comprising the cylindrical bearing casings 112a and H211 asshown in Figures 7 and 8 and having journaled therethrough their ownspindles H5, together with rotors H6 at their inner ends and tools suchas grinding wheels as 1a and lb at their opposite ends, may then beinterchangeably associated in the split bearing of the support [80, withthe motor rotor carried thereby in cooperative relation to the statorsecured to the support I68.

From the foregoing description of certain embodiments of this invention,it will be understood by those skilled in the art that various otherarrangements of interchangeable units, each comprising a bearing casing,a spindle journaled therethrough, and a rotor at one end and a tool or awork holder at the other, may be employed, all interchangeable withother units having different tools or holders carried by their spindles.

It is also evident that other changes and modifications might be madewithout departing from the spirit or scope of this invention.

I claim:

1. In combination, a unit comprising a spindle, a motor rotor on one endof said spindle, a device at the opposite end of said spindle, and aspindle bearing casing between said rotor and device and within whichsaid spindle is journaled, a support, a motor stator comprising a coreand frame carried by said support, and means for removably securing saidunit with the motor rotor in operative relation to said stator.

2. In combination, a unit comprising a spindle, a motor rotor on one endof said spindle, a device at the opposite end of said spindle, and aspindle bearing casing between said rotor and device and within whichsaid spindle is journaled, a support, a motor stator comprising a coreand frame carried by said support, said casing and support havingflanges mating when said rotor is in operative relation to said stator,and removable means for securing said flanges together.

3. In combination, a unit comprising a spindle, a motor rotor on one endof said spindle, a delvice at the opposite end of said spindle, and aspindle bearing casing between said rotor and device and within whichsaid spindle is journaled, a support, a motor stator carried by saidsupport, said casing being cylindrical in contour, and said supporthaving a clamping portion for securing said cylindrical casing, andclamping said unit in position with its rotor in operative relation tosaid stator.

THOR H. LJUNGGREN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Great Britain Sept. '7, 1936

